To increase the performance of a gas turbine engine, it is necessary to increase the temperature of the gases leaving the combustion chamber. The components of the engine bathed by these gases are therefore subjected to high thermomechanical stresses. They are protected by making cooling air drawn off from the compressor flow into channels provided beneath the wall and discharging said air into the gas stream via small-diameter orifices that are made so as to form a film of protective gas between the wall and the flow of hot gas. The components affected by this treatment are essentially the distributor sectors, consisting of one or more radial airfoils between two platforms in ring sectors by which the gas stream is bounded, and also the moving blades of the first turbine stages. The mechanical behavior and the lifetime of the components are improved by this means.